Apparatus for non-destructive hyperthermia therapy

ABSTRACT

Apparatus for non-destructive hyperthermia therapies, characterized in that it comprises means for generating electromagnetic radio-frequency radiations, connectable to means for the application of said radiations to the human body.

The present invention refers to an apparatus for non-destructivehyperthermia therapies.

A deep, non-destructive hyperthermia, that is, one in which theoperating temperature is below 45÷48° C., is known to be usefullyapplied to various pathologies such as, for example, rheumatoidinflammations, arthritides, tendonitises, etc. However, owing to thethermal characteristics of the skin (which is a good thermal insulator)and to the circulation of liquids below the skin itself (presence ofvenous and arterial circulation) it is impossible to achieve asignificant deep hyperthermia through a simple heat conduction. In fact,in order to raise the internal temperature by a few degrees it would benecessary to increase the surface temperature to such a level that theskin would burn.

Currently, for the treatment of the said pathologies, there are usedapparatuses of various type such as, for example, microwaves orultrasound or laser-operated, or of electroanalgesic type, etc.

The object of the present invention is to provide a new apparatus forhyperthermia therapies able to solve the above problem with efficacy andwithout damaging the skin.

This result has been achieved, according to the invention, by adoptingthe idea of making an apparatus having the characteristics indicated inthe claim 1. Further characteristics being set forth in the dependentclaims.

Among the advantages of the present invention one is that the apparatusresults very effective in the treatment of many pathologies, such asrheumatoid inflammations, tendonitises, acute inflammatory forms, etc.In the sports medicine as well, these procedures can be suitably appliedin subjects suffering from sprains, muscle strains, contusions, etc.

Another advantage is that the invention allows a drastic reduction ofthe pain, in relatively short times (in comparison with the knowntechniques). Moreover, the apparatus is simple to use, easy to operate,and it maintains its characteristics also after prolonged periods ofoperation.

These and other advantages and characteristics of the invention will bebest understood by anyone skilled in the art from a reading of thefollowing description in conjunction with the attached drawings given asa practical exemplification of the invention, but not to be consideredin a limitative sense, wherein:

FIG. 1 is a block diagram of a possible embodiment of the apparatus inquestion;

FIGS. 2 and 3 show two graphs relating to the temperature's trend withintwo sections of the tissue heated up in conformity to the presentinvention according to two different procedures;

FIGS. 4A and 4B show in plan view from above, an embodiment of twoelectrodes made according to the invention;

FIGS. 5A and 5B show in plan view from above, a further embodiment oftwo electrodes made according to the invention;

FIG. 6 is a block diagram of a further possible embodiment of theapparatus in question.

An apparatus for non-destructive hyperthermia therapies according to thepresent invention, is able to transmit energy to the tissues byradio-frequency electromagnetic radiation. The apparatus is able to heatthe tissue beneath the skin regardless of the barrier of thermalinsulation that the same skin stands up to the heat-conductingprocesses. In fact, the overheating of the underlying tissue is mainlydue to the forces produced by the mid-frequency electromagnetic field,which forces, by interacting with the molecular ions present in thetissue, generate heat.

With reference to the non-limiting block diagram of FIG. 1, theapparatus comprises an RF generator, designated by 1 as a whole. In theexample, encircled by a discontinuous line are a plurality of elementsmaking up a generator 1 consisting of: an oscillating circuit 2, adriver 3 and an amplifier 4. On output from the amplifier 4 there areprovided two connectors 40 and 41 for connection with correspondingelectrodes 5 and 6, to be described later on.

The power of the generator 1 can be adjusted so as to result below apreset threshold; a maximum value may be provided, for example, of 20 W.

Again with reference to the embodiment of FIG. 1, the generator 1 iscontrolled by a set of circuits which fulfil different functions.

In particular, it is possible: to set the desired temperature reached bythe skin; to automatically adjust the output power, so as to keep thetemperature of the skin surface at the preset value; to measure theimpedance in correspondence of the contact electrodes 5 and 6, theoutput power and the temperature reached under the delivering electrode;to set the duration of the treatment.

To fulfil the above functions, provision may be made for the followingcomponents.

Interposed between the oscillator 2 and driver 3 is atemperature-controlling circuit 7 which controls the power value and isconnected to a comparator 8. On input to the comparator 8 are twotemperature-related signals, a reference signal programmable by theelement designated by the block 9, and a signal detected by a detectorcircuit 10 connected to relevant sensors 52 (in the example to bedescribed below, being disposed and operating in correspondence of theactive electrode 5) which detect the temperature on the skin surface.Associated with the detector circuit 13 is a visualization means, such adisplay 13, which allows the detected value to be controlled visually.The comparator circuit is connectable to an interface device 80 to belinked, for example, with the gate 88 of a computer to allow theprocessing of the relevant data.

Also connected to the amplifier 4 are two measuring circuits 81 and 82intended, respectively, to measure the output power and the impedance incorrespondence of the contact electrodes 5 and 6. The two measuringcircuits 81 and 82 can be connected, as shown in FIG. 1, to relevantdisplays 83 and 84 for the visualization of the detected values.

Moreover, connected to the RF-radiations generator 1, is a timer circuit85 able to set the treatment duration.

As above mentioned, on output from the generator 1, more specifically,downstream of the amplifier 4, there are provided two electrodes 5 and6. In particular, as illustrated in the example of FIGS. 4A-5B, theelectrodes are made up of a first contact plate 6 (shown only in FIG.4A) which represents the reference electrode 6, and of a second plate 5,of smaller dimensions and provided with a thermocouple, which representsthe active electrode 5. By way of example, the first plate 6 may exhibita surface area of about 80 cm² and be provided with a connector 55associable with the connection 41 provided on the generator 1.

Both the reference electrode 6 and active electrode 5 are to beconsidered of disposable type or, at the most, reusable on subsequentapplications for the same patient, and they can be made through the sametechnology.

The active electrode 5 may be, as already mentioned, either ofdisposable or reusable type; it being preferably made up of a conductivemembrane having suitable dimensions. For example, the active electrodemay exhibit an area extending over (10×10) cm by using larger referenceplates, for example of (15×15) cm. The active electrode is provided witha connector 51 suitable for linking the RF generator 1 via theconnection 40, for example. The membrane of the active electrode 5 iscoated with a layer of adhesive and conductive gel able to ensure aproper and full contact with the patient's skin. The electrode,moreover, is provided with one or more temperature sensors such as, forexample, one or more thermocouples 52. This makes it possible, as aboveindicated, to monitor in real and continuous time the temperaturereached by the skin itself; besides, the value detected by thethermocouple 52 also allows continuously adjusting the delivery of RFpower, so as to keep the surface temperature at a steady valueapproximately matching that of the preset threshold.

The structure of the active electrode 5 shall have shapes and dimensionssuited for the region of the body to be treated. The shaping will betherefore rectangular, square, rounded, circular, etc.

The temperature sensors 52 may be incorporated in the same electrode(such as in the examples of FIGS. 4A and 4B) so as to result themselvesdisposable when the electrode is of this type. Alternatively, as shownin the examples of FIGS. 5A and 5B, the electrodes may exhibit a seat 53complementarily matchable with a corresponding connector of the sensor.

Should the regions interested by the pathology be of significantextension, an embodiment of the invention would be used able todistribute the RF sequentially over more active electrodes, thereference electrode being the same, so as to avoid the delivery of highpower as necessary when using larger electrodes.

An example of such embodiment is diagrammatically illustrated in FIG. 6wherein the components similar to those of FIG. 1 are given the samereference numbers, numeral 5 indicating the complex of elements thatdefine the active electrode. The various active electrodes (which, inthe non-limiting example, are in number of three and designated by 501,502 and 503), all of them having the same dimensions, could be sodisposed as to cover the interested region and connected with aswitching system 50 linking them sequentially to the RF source composedof the generator 1. The element 50 could be made up of a sequentialswitch connected to the output 40 of the RF generator 1 and to the threeactive electrodes 501, 502 and 503.

This will make possible to heat a larger area with the same poweralthough, obviously, with longer application times. The controltemperature can be measured on only one (in FIG. 6 designated by 501) ofthe active electrodes being used, with provision of maintaining thiselectrode connected for a time a little longer than for the others, inorder to make sure that the reading of the reference temperature resultshigher than that of the others.

During the experimentations being carried out, it has been found that,in order to provide a proper heating of the tissue, the specificrecommended power to be applied (measured in Watt/cm²) is in the orderof 0.3 W/cm².

Moreover, during the experimentation, the presence of the interface 80,especially of analog/digital type, has shown to be very useful, althoughthe instrument is able to operate autonomously as well. To achieve astandardization of the application procedures for the individualpathologies during the experimentation, and for a correct filing upon aroutine usage as well, use is made of the analog/digital interface 80allowing a direct connection, via a serial gate 88, with a computerwhich, when provided with a dedicated software, is able to register allthose parameters such as output power, operating impedance and skintemperature.

During the experimentation, the preset apparatus was used forapplications on subjects affected by acute inflammatory forms andsuffering from pains in, respectively, a knee, first phalanx of thethumb with a swelling at its joint, and in the lumbar position of theback.

In all these cases, the application time was set on 25 minutes. Afterthe first application, each patient experienced a significant reductionof the pain.

The applications were repeated at regular intervals of 24 hours and,upon the fourth application, all the patients had their pains completelyrelieved and, in addition, the swelling at the joint between themetacarpus and the first phalanx of the thumb virtually disappeared.

From this approach in the treatment it seems that the non-destructivehyperthermia produced from a radio-frequency electromagnetic radiationis able to immediately raise the pain's threshold of the local receptors(attenuation or disappearance of the pain upon completion of anindividual application) and to have a significant anti-inflammatoryeffect.

FIGS. 2 and 3 refer to an in vitro experimentation and provide somevalues relevant to parameters of the instrument used for themeasurements. These figures point out that the heating of the tissue, asobtained from the radio-frequency electromagnetic radiation produced bythe said instrument, is able to overcome the thermal barrier opposed bythe skin. In fact, the graph of FIG. 2 shows the surface temperature andthe temperature at 2 cm deep in the tissue—with a uniform startingtemperature—designated, respectively, by the references T2 and T1. Inthis case, as illustrated by the graph, the two temperatures can beconsidered as overlapping. Plotted in the upper part of the graph is theoutput W power-versus-time curve.

FIG. 3, instead, show the trend of the same temperatures within thetissue when the starting temperature is not uniform; in fact, in thiscase the in-depth temperature T1 is maintained by a heat source, otherthan the said instrument, at a value which is 7° C. higher than thesurface-relating T2. As can be seen in the graph, such ΔT is maintainedthroughout the measurement. This shows how it is possible to achieve adeep hyperthermia by a radio-frequency electromagnetic radiation also inthe presence of the thermal insulation provided by the skin.

Practically, the construction details may vary in any equivalent way asfar as the shape, dimensions, elements disposition, nature of the usedmaterials are concerned, without nevertheless departing from the scopeof the adopted solution idea and, thereby, remaining within the limitsof the protection granted to the present patent.

1. Apparatus for non-destructive hyperthermia therapies, characterizedin that it comprises means for generating radio-frequencyelectromagnetic radiations, connectable to means for the application ofsaid radiations to the human body.
 2. Apparatus according to claim 1,characterized in that the said means comprise an active electrode and areference electrodes, the said active electrode being provided withmeans for the detection of the skin's temperature.
 3. Apparatusaccording to claim 2, characterized in that the said means for thedetection of the skin's temperature are made up of at least a sensorincorporated in the electrode.
 4. Apparatus according to claim 2,characterized in that the said means for the detection of the skin'stemperature are made up of at least a sensor which can be connected tothe apparatus and removably associated with the active electrode incorrespondence of a relevant seat thereof.
 5. Apparatus according toclaim 2, characterized in that the said means for the detection of theskin's temperature are connected to a control circuit connectable to andacting on said means for generating radio-frequency radiations. 6.Apparatus according to claim 2, characterized in that the saidelectrodes consist of conductive plates or membranes.
 7. Apparatusaccording to claim 2, characterized in that the structure of the activeelectrode is complementary shaped with respect to the body's region ofthe patient to be treated.
 8. Apparatus according to claim 2,characterized in that the said reference electrode has dimensions largerthan those of the active electrode.
 9. Apparatus according to claim 2,characterized in that it comprises more active electrodes connected to aswitch device able to connect in sequence said active electrodes to saidmeans for generating radio-frequency radiations.
 10. Apparatus accordingto claim 1, characterized in that it comprises means for adjusting thetemperature reached on the skin and able to vary the output power inorder to keep the skin's temperature at a preset value.
 11. Apparatusaccording to claim 1, characterized in that it comprises means formeasuring the output power and the impedance in correspondence of theapplication means.
 12. Apparatus according to claim 1, characterized inthat it comprises means to preset the duration of the treatment. 13.Apparatus according to claim 1, characterized in that it comprises meansfor connection with an electronic processor.